Stained glass windows bathe this botanical garden in cosmic light.

The massive cave church of Cairo's Zabbaleen community is one of the largest Christian churches in the Middle East.

An ancient city exhumed from the depths of the ocean.

Whimsical artist house in the New Jersey woods.

Golden Gate Park's historic collection of plants.

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

Olfactory delights in San Francisco's Botanical Gardens.

Relics of the 1894 Midwinter Exposition continue to delight visitors today.

Carnivorous plants, medieval aphrodisiacs, and the largest original wood structure glass conservatory in the western hemisphere.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

A winding path built in secret on the edge of the continent.

An artsy hidden staircase leads to breathtaking views of San Francisco.

Pilgrims each carried a brick to the top of Mount Monserrate to help build this historic sanctuary in Colombia.

The centuries-old trees are draped with Spanish moss to make them look like wizened elders.

This colonial town in Colombia sits around the largest stone paved square in South America.

An ancient city hidden in the heart of the Sierra Nevada mountains.

Hidden amid the tropical forest in the Caribbean Sea are the decaying ruins of the Cocaine King's luxurious island party home.

An explosion of natural color known as "the river that ran away from paradise."

A dangling church built over a Colombian gorge.

Perched atop the highest hill in Cartagena, this 17th-century convent offers spectacular views of the city.

66,000 pieces of art, donated by one of the world's richest men.

Frida Kahlo's childhood home, now a museum of her life and works.

Unparalleled stargazing, one of Colombia's best observatories, and a swimming pool can all be found in the middle of this ancient tropical forest.

An inspired museum dedicated to the patron saint of enslaved people, inside the cloisters where he lived and died.